diffuse bounce issue with brute force

[FSGFX]

i did a little gi test with vray and wondering why is there still no light on the wall..?
im using 8 gi bounces... there is only one area light on the end of the tunnel...



all the other render engines got it working with 5 bounces...

whats happending here.?

[t.petrov]

What VRay version are you using?
What light are you using?

I've just tried it with VRay Rect Light and it works as expected. Even 3 GI bounces are enough to see the GI on the wall.

[vlado]

It would be best to post your scene - my own tests produce identical resutls. Other than that, make sure the material colors and light intensities match. From what I remember, Arnold may do gamma correction on the shader and/or light colors. Make sure that output gamma matches too.

Best regards,
Vlado

[FSGFX]

in sure i did something wrong...
here is the scene...

maya 2015... vray 3....

[FSGFX]

a little note on all images i pushed the gamma to 1.5 in the renderview....

[Morbid Angel]

I dont have maya 2015 here, but if your adaptive amount was set to 1, then its possible dmc sampler just skipped over those areas?

[FSGFX]

adaptive is set to 0.85..
and im using the progressive sampler...
but the adaptive sampler shows the same image...

[vlado]

The material is too dark... I think the linear workflow option needs to be off. Still looking though...

Best regards,
Vlado

[FSGFX]

i did that already... but its not much better...

[vlado]

So far looks ok for me... I did V-Ray and rman, getting to Arnold now.

Best regards,
Vlado

[jasonhuang1115]

cool, Vlado. Can you tag the render time for all three when you get to Arnold?

[vlado]

That would be a bit hard... For V-Ray and prman, I can use progressive rendering to let them run for the same amount of time, and compare the noise (but I also used DR with V-Ray to help with the test times). However rman is not very efficient when doing progressive rendering, so it would not be quite fair. Arnold can't do this, so I need to fiddle with GI samples to see what would give me acceptable time vs noise. Besides, I have the initial Arnold demo version from the beginning of last year and I'm sure things have changed since then. Finally, I'd really use the light cache in V-Ray for the secondary GI engine.

Best regards,
Vlado

[vlado]

Here is the V-Ray and Arnold images and scene.

Best regards,
Vlado

[jasonhuang1115]

Thanks for the explanation Vlado....You can get latest demo from Solid Angle's site if interested in doing this with the latest version...for PRMan, are you testing with the reyes or the RIS integrator?

[FSGFX]

thanks for testing vlado... i see you upped the shading rate to 16... was this the only thing you changed..?
its much better now thanks...